1. Field of Invention
The present disclosure relates generally to the field of electronics and, more particularly, to devices and methods that dissipate heat from electronic components.
2. Discussion of Related Art
Modern electronic components produce excessive amounts of heat during operation. To ensure that the components do not overheat, system designers attach convective heat sinks to cool these components, by providing an efficient heat transfer path from the devices to the environment. A typical convective heat sink is designed to transfer heat energy from the high temperature component to lower temperature of the surrounding air. Such typical heat sinks attach to the components through a base and include fins or pins to increase the surface area of the heat sink within a given space.
FIG. 1 shows a well-known embodiment of a heat sink 100. The heat sink may be extruded from aluminum and comprises a heat dissipation component 102, having parallel fins 104 that extend perpendicularly from a base 106. By increasing the surface area of the heat sink 100, the heat transfer capacity of the heat sink 100 increases. The surface area of the heat sink 100 may be increased by extending the fins 104 in one direction away from the electronic component, thus creating an extruded fin profile, or by providing more, smaller fins. The air heated by the component 102 passes through the fins 104, thus transferring heat away from the device to the surrounding environment.
However, because the fins 104 are essentially flat plates, air flowing in the same direction along the surface of the plates forms a micro layer of stagnant air. This micro layer of air causes air flow to decrease near the surface of the fins, decreasing the overall air flow through the heat sink. This effect results in a decrease of the amount of heat dissipated from the electronic component that is transferred to the surrounding environment.
The efficiency of the heat sink design is measured by the thermal resistance between the heat sink and the ambient air. The micro layer of stagnant air causes decreases of air flow through the heat sink, thus increasing the thermal resistance of the heat sink and decreasing its efficiency. To compensate for the lower efficiency, designers are compelled to create larger and heavier heat sinks for electronic components that dissipate large amounts of heat. Although heat sinks vary in design, in general, the more surface area a heat sink has, the lower the thermal resistance. Particularly demanding cooling applications may require a number of heat sinks to be used concurrently, further increasing the volume and weight of the heat sink system. By increasing the volume, weight and the number of components of the heat sink, the cost increases due to increased material and more complex tooling. Large heat sinks may also be hard to implement in situations in which the space is constrained.